Render looks better in prepass than it does in the final render

The title pretty much explains it. I'm new to rendering so please excuse me if the question is trivial

Lighting is a mix of prepass and lightcache. So, you are getting a mix of both. Best would be to lower the light value slightly, also change the material on the building. It looks like it is set to white whereas you will actually want it somewhat grey to help prevent blow out. So, make it greyer until you get what you want. If you are just using the colour picker try setting the number of white at about 180 and bring it higher if needed to create a result you like.